Improvement in sewing-machines



M 2Sheets--Sheet1 1. & R. BLAKE.

Sewing-Machines. N0-.149,565, Patented April 14, 1874.

FICI.

HI'I

&\\ n

UNITED STATES JAMES BLAKE, on PROVIDENCE, RHoDE ISLAND, AND ROBERT BLAKE, or

PATENT OFFICE.

NEWARK, NEW JERSEY.

IMPROVEMENT IN SEWING-MACHINES.

- Specification forming part of Letters Patent No. 149,565; dated April 14,1874; application filed March 14, 1874.

To all whom it may concern:

Be it known that we, JAMES BLAKE, of Providence, in the county of Providence and- Stateof Rhode Island, and ROBERT BLAKE, of Newark, in the county of Essex and State of New Jersey, have invented new and useful Improvements in Sewing-Machines; and we do hereby declare that the following specification, taken in connection with the drawings furnished, is a full, clear, and exact description, which will enable others skilled in th art to make and use the same.

Our invention relates to the employment and arrangement of certain devices forming the details of a sewing-machine of the class known more particularly as leather machines, yet it may be employed for the various purposes to which similar machines may be adapted. Said details may be used or applied separately or in combination; and our invention consists in a shutte provided with a spring'tension device, constructed as hereinafter described, for the purpose of producing tension on the shuttle-thread, and preventing its kinking, by holding the same in a desired position while the shuttle is retreating; also, in an improved spring tension device arranged upon the top or neck of a sewing-machine, and having means for retaining the springs at a proper distance apart centrally, forming thereby a slightly-tapered opening or space, so that the thread, in its passage between the springs toward the needle, may not be restrained by abrupt corners, which so often obstruct and cause irregularities in the feed; also, in the take-up devices, constructed as "hereinafter described, the said take-up being secured at the inner part of the frontplate of the stationary arm by a single screw or pin,

- upon which it vibrates, being actuated by a V cam formed of the crank, or by a separate arrangement, while the strain or pull upon the thread is controlled by an adjustable spring attached to the lever and the plate or the corresponding part of the stationary arm. Gonsequently, instead of a rigid pull upon the thread under any and all circumstances, our arrangement of devices compensates automatically for any unevenness of material operated upon; hence a uniform evenness of stitch is maintained throughout, regardless of any definite thickness which may be placed between the cloth-plate and presser-foot; also, in an arrangement of devices for elevating the wheel or presser-foot at the proper time, consisting of a lever pivoted to the head by an adjustable screw in rear of the needle and presser bars, said lever being actuated by a cam, which may be either formed upon the crank-plate or otherwise, and the other end of the lever engages a projection upon the presser-bar.

Referring to the drawings, Figure 1 represents a sectional view of a sewing-machine embodying our improvements. Fig. 2 is a sectional view of a forked lever with offset prongs, showing also the double cam or cams.

Fig. 3 shows details of the tension device with its double-shouldered screw, &c.; Fig. 4, secitions of the automatic foot-lift and its connecting parts; Fig. 5, take-up device, its means 1 for adjustment, and cam; Fig. 6, shuttles with our improvement applied thereon.

A and B, arm and bed of a sewing-machine,

to which are attached nearly all of the principal g parts-necessarytoperformthe'desiredfunctions. K O is the upper driving-shaft, to which cams are attached as mediums to impart motion to the needle--bar,'takeup, resser-foot, levers, &c., which operate the shuttle, feed, &c. D is a cam, which may be formed upon the crankplate, or may be constructed and applied separately, arranged, for convenience, in the rear of the front part of said crank-plate, to allow free action to the parts in its front. E is the crank-plate secured at or near the end. of the shaft 0, which serves as a cam to operate the thread take-up as well as to operate the needie-bar; .F, crank-pin, applied and used to en-, gage the needle-bar in the usual manner; H,

gaging cam D. The stud, which servesasa pivot, passes through the foot, near its heel, which is formed at a right or oblique ngle to the main lever by bending or otherwise. This foot engages, near its toe, the under side of a pin or other projection on .the presser-bar, which is lifted automatically, and held suspended for a sufficient time to enable the operator to turn the work'operated upon at will. In operation, the elevation of the presserbegins at the moment the needle enters the .material, rising clear above the work, remaining in suspension while the needle performs its first and second motion, but immediately engages and holds the materials fast at the moment of the final ascent of the needle. This action of the needle-bar not only enables the operator to have complete control over the material operated upon, but allows the needle to descend through the material perpendicularly, which would otherwise be inclined in a direction somewhat oblique to its natural course, in consequence of striking upon the sloping side of the indent caused by the pressure of the presser bar or foot, and which has the effeet to cause the material to cling to the needle in its upward motion, producin g a lateral strain,

' which is apt to break the needle; K, the adjustable stud to fix the position of the automatic foot-lift for the varying thicknesses of materials; L, arm and wheel, serving as a presser-foot attached to the presser-bar; M,-cam or cams secured to the upper driving-shaft, within the arm, (see Fig. 1,) the principal features of which consist in their form and the relation of their cireiunferential surfaces to each other, which impart a certain desired motion to the shuttle through the medium of a vertical pivoted vibrating lever, n, and the horizontal shuttle-carrying lever. The lever n, which is actuated by cam, is provided with prongs forming a fork,'which prongs are offset from a line right and left, (as shown in Fig. 2,) each resting at points opposite on the cam or cams.

These cams may be constructed separately or in one piece, may be shaped to a form, or by any other of the known ways, and secured in position in the usual manner. The forked lever may be formed by casting or otherwise.

said device is secured to the inner side of the upper part of the front plate or cap which covers the needle and presser bars, by screw or other means, upon which the lever vibrates, and is actuated by the revolvingcam E. The end of the projecting arm, which is provided with an eye, and through which the thread passes toward the needle, is so formed as to project through an opening in the lower part of the aforesaid cap'. (See Figs. 1 and 5.) A spring is applied to the U-shaped part, the op-. posite end of which is attached to a stationary part of the head or cap near the top, as shown.

This spring should possess the proper strength to hold the trailing part of the lever upon the cam, (while the latter is rapidly revolving,) as well as a sufficient elasticity to prevent breaking of the thread, and at the same time draw the under thread to the proper extent, holding the same firmly without releasing it until the upper thread is tightly drawn by the action of the shuttle and its spring, by which means the under seam is made to present the same appearance as the upper one, and a firm stitch is produced under all circumstances. Arranged upon or near the top of the head is an adj ustable ear or loop, W, to which the springs may be attached, which is moved and held in position by screws Z and Z, (more clearly shown in Figs. land 5 of the drawing,) which enables the operator to readily regulate the strain or pull upon the thread, which is desirable when the change is made from the heavy wax thread for leather work to the light cotton, &c., for light fabrics, &c. The thread tension P is composed of two thin flat springs, lying together and resting upon projections for that purpose upon the top of the arm. These springs are separated at their centersforming thereby a tapering opening to receive the thread as it passes between and toward the needle-bar, so as to prevent the breaking of the thread, which is so apt to occur when abrupt comers are met with--by means of a screw provided with a double shoulder. (See Fig. 3.) The two springs are provided with holes at or near their centers, through which the screw is admitted, the hole in the top one being about one-sixteenth of an inch, more or less, larger than the one in the lower spring, so that the shoulder of the screw which passes through it may cover the one below. About one-sixteenth of an inch will form a sufficient space; but this space may be varied, if desired.

We would remark that the object may be accomplished by placing a washer or other device between the springs, applying the pressure in the usual way.

S is a perforated spring, adapted to produce tension, and secured to a shuttle, and through the openings the shuttle-thread is laced, and the pressure of the spring upon the thread gives the required amount of tension. Arranged at its side, and opposite or farthest from the shuttle-race face, is a spring-finger, S, (represented in the drawing as forming a part of the perforated spring S,) although operating independently. The object of this device is to hold the slack thread-in the retreat of the shuttle, to prevent it from kinking, which is accomplished by passing the thread from the perforations in spring S under the latter and finger S. In the forward motion of the shuttle, the thread will be carried or drawn under the finger to a point near or at its loose end, and in its retreat the thread is so held as to support its slack, and thereby prevent the difficulties that are otherwise apt to occur. This loose yielding end S acts alike upon all sizes I of thread, waxed or otherwise. The main 'part of the spring, (indicated at S,) as well as the spring-finger S, is made of steel or other suitable metal, and made to rest upon a flattened surface of the shuttle provided for that purpose with an elastic pressure, for the purposes aforesaid. The main part (or S) is provided with hook ends, one of which looks into an opening for that purpose in the shuttle near the forward part, as shown. The other is held in a niche at the heel.

Having described our invention, we claim- 1. The tension device for the shuttle, consisting of the perforated spring S and the curved spring-finger S, operating as and for the purposes set forth.

2. The combination, with the two springs -P, forminga thread-tension, of the doubleshouldered thumb-screw a, substantially as set forth.

3. The combination of the take-up device 6, the spring X, ear W, and its adjustingscrew Z, substantially as set forth.

4. The combination, with the presser-foot shaft, of the foot-lift J and its adjustable bearing K, all arranged and operated by the cam D, substantially as set forth.

JAMES BLAKE. ROBT. BLAKE. 

